Incidence Of Dysrhythmias Research Articles

Incidence of the Oculocardiac Reflex using Isoflurane & Halothane during Enucleation Surgery under General Anaesthesia at NIO&H - A Comparative Study

Background: The Oculocardiac reflex (OCR) is a well-known complication of ocular surgery involving direct or indirect manipulation of the eye or ocular adnexa. While most commonly associated with eye muscle surgery, with a reported incidence of 40-93%, it is prevalent during traction on the extraocular or eyelid muscles, compression of the globe, intraocular and retro bulbar injection, iris traction, retinal reattachment surgery and enucleation procedures and may manifest as a wide range of arrhythmias including ventricular bigeminy, bradycardia and asystole. Occurrence of the reflex in eye muscle surgery has been documented to increase with hypoxia and decrease with aging and premedication with anticholinergics, namely glycopyrrolate or atropine.
 Objective: The purpose of our study was to determine the degree of change in heart rate (HR) and systolic blood pressure (SBP) during Enucleation surgery in patients anaesthetized with equipotent concentrations of Isoflurane or Halothane breathing via a laryngeal mask airway (LMA).
 Methods: The study was designed as a prospective randomizedstudy. Fifty patients, having selected for Enucleation were randomized to Isoflurane (I) or halothane (H) in 66% nitrous oxide at 1.3 minimum alveolar concentration. Patients breathed through a laryngeal mask airway (LMA) and were not pretreated with anticholinergics.
 Results: The Oculocardiac reflex (OCR), defined as a 20% decrease in heart rate (HR) from baseline, dysrhythmias or sinoatrial arrest concomitant with ocular muscle traction occurred less frequently with Isoflurane than with halothane (I: 37%, H:78%, P = 0.009). The HR during induction was higher with Isoflurane (I: 110 ± 13 bpm, H: 100 ± 15 bpm, P = 0.002). The lowest HR occurred with halothane (I: 94 ± 22 bpm, H: 72 ± 19 bpm, P = 0.001). The incidence of dysrhythmias was higher in the halothane group (I 4%, H: 42%, P = 0.004). Isoflurane may be a more suitable anaesthetic than halothane for operations involving traction on the ocular muscles with controlled respiration in patients because of reduced incidence of OCR with slightly higher airway irritability.
 Conclusion: Some patients experience a sudden slowing of the heart when the surgeon pulls on the eye muscles during Enucleation operations under anaesthesia. We found that Isoflurane was associated with a lower incidence of the OCR but relatively higher airway irritability compared with halothane. The oculocardiac reflex possesses the potential for significant morbidity and mortality. While some have documented factors affecting the OCR during eye muscle surgery, our data could not prove such a relationship during enucleation.
 J. Natl. Inst. Ophthalmol. 2022;5(1):21-26

The Incidence of Dysarrhythmias, Their Types and Outcomes in Patients Hospitalized with COVID -19

Background: COVID-19 infection started in China and became a pandemic, the SARS-CoV-2 virus mainly affects the respiratory system but can insult the cardiovascular system as well, higher rate of cardiac arrhythmias noted during the pandemic, and many studies showed that COVID-19 (especially hospitalized patients) can develop different types of arrhythmias which cause higher mortality rate. Objective: To assess the incidence of dysrhythmias and their types and outcomes in hospitalized patients with COVID-19 in Erbil city. Patients and Methods: Patients with documented COVID-19 infection admitted in Erbil Teaching Hospital respiratory care unit and coronary care unit from 1-8-2020 to 30-10-2020 had been included (255 patients) in this cross-sectional study, demographic data, and outcomes were reported, the ECG analyzed by cardiologists and the type of arrhythmia documented. Results: Mean age was 47±12 years, 61% of the patients were male, 25% of them had previous cardiac diseases, 20% diabetes, 16% multiple comorbidities, 8% hypertension, 8% obesity and 23% had no comorbidities, 20.7% of in-hospital patients developed dysrhythmias, 5.9% of them developed sinus tachycardia, 4.7% atrial fibrillation, 3.9% ventricular premature contractions, 2% ventricular fibrillation, 1.9% ventricular tachycardia and 1.9% heart blocks. Most of the patients who developed ventricular arrhythmias, atrial fibrillation, and heart block had previous comorbidities 82%, 62%, and 80% respectively. Arrhythmias caused a higher in-hospital mortality rate (39.6% versus 21.7%) especially among male patients (mortality rate in male patients 43% compared with female patients 33%). Conclusion: Most of the admitted cases were male. Most of them had comorbidities especially previous cardiac diseases. Sinus tachycardia, atrial fibrillation, and ventricular extra-systoles were the most frequent arrhythmias. The mortality rate was increased by arrhythmias mainly in male patients. Keywords: COVID-19, Dysrhythmias, Outcomes, Pandemic

Salbutamol in acute organophosphorus insecticide poisoning – a pilotdose-response phase II study

Background: Treatment of acute organophosphorus (OP) insecticide poisoning is difficult, with many patients dying despite best care. Pre-clinical studies have shown benefit from salbutamol, possibly due speeding alveolar fluid clearance or reducing bronchoconstriction. In this small pilot dose-response study, we aimed to explore whether addition of nebulized salbutamol to standard care might improve resuscitation.Methods: We performed a single-blind phase II study comparing the effect of two different doses of nebulized salbutamol versus saline placebo, in addition to standard treatment. Primary outcome was oxygen saturations over the first 60 min of resuscitation; secondary outcomes included heart rate, incidence of dysrhythmias, time to ‘atropinization’, atropine dose required, and mortality.Result: Seventy-five patients were randomized to receive 5 mg (Salb5, n = 25) or 2.5mg (Salb2.5, n = 25) of salbutamol, or saline placebo (NoSalb, n = 25), by nebulizer. Oxygen saturations did not differ between groups over the first 60 min of resuscitation (median AUC NoSalb: 1376 [95% CI 1282 to 1470], Salb2.5: 1395 [1305 to 1486], Salb5: 1233 [1100 to 1367]; p = .9898). Heart rate was also similar across the three arms. Median time to full atropinization, and atropine dose required, were the same for all three arms (NoSalb 15.0 [10–16] min and 12.6 [8.0–13.4] mg, Salb2.5 15.0 [10–16] min and 12.6 [9.3–16.8] mg, and Salb5 15.0 [10–20] min and 12.6 [10.7–20.6] mg; p = .4805 and p = .1871, respectively). Three (12%) patients died in the Salb2.5 and Salb5 groups and two (8%) in the NoSalb group.Conclusion: This pilot study, within the limitations of its small size and variation between patients, found no apparent evidence that administration of nebulized salbutamol improved resuscitation of patients with acute OP insecticide self-poisoning. The data obtained provides a basis to design further studies to ultimately test the role of salbutamol in OP insecticide poisoning.

Effects of conventional vs high-dose rocuronium on the QTc interval during anesthesia induction and intubation in patients undergoing coronary artery surgery: a randomized, double-blind, parallel trial.

Myocardial ischemia, as well as the induction agents used in anesthesia, may cause corrected QT interval (QTc) prolongation. The objective of this randomized, double-blind trial was to determine the effects of high- vs conventional-dose bolus rocuronium on QTc duration and the incidence of dysrhythmias following anesthesia induction and intubation. Fifty patients about to undergo coronary artery surgery were randomly allocated to receive conventional-dose (0.6 mg/kg, group C, n=25) or high-dose (1.2 mg/kg, group H, n=25) rocuronium after induction with etomidate and fentanyl. QTc, heart rate, and mean arterial pressure were recorded before induction (T0), after induction (T1), after rocuronium (just before laryngoscopy; T2), 2 min after intubation (T3), and 5 min after intubation (T4). The occurrence of dysrhythmias was recorded. In both groups, QTc was significantly longer at T3 than at baseline [475 vs 429 ms in group C (P=0.001), and 459 vs 434 ms in group H (P=0.005)]. The incidence of dysrhythmias in group C (28%) and in group H (24%) was similar. The QTc after high-dose rocuronium was not significantly longer than after conventional-dose rocuronium in patients about to undergo coronary artery surgery who were induced with etomidate and fentanyl. In both groups, compared with baseline, QTc was most prolonged at 2 min after intubation, suggesting that QTc prolongation may be due to the nociceptive stimulus of intubation.

Myocardial remodelling induced by repeated low doses of isoproterenol

In the present work, the effect of isoproterenol on the electrical properties of the rat heart and on the cytoarchitecture of the surviving cardiomyocytes was studied. Myocardial remodelling was induced by the daily administration of 5 mg/kg isoproterenol (Iso) for 7 days. Administration resulted in a significant increase (52%) in the ratio of left ventricular weight to body weight. ECG voltage criteria confirmed the presence of left ventricular hypertrophy. QT interval prolongation by 23% and 58% was found in Iso rats and in the corresponding isolated hearts, respectively. Spontaneously beating Iso hearts had a higher incidence of dysrhythmias. The surviving cardiomyocytes showed an irregular shape with cytoplasmic processes rich in ribosomes and rough endoplasmic reticulum. In these regions, myofibril disorganization and mitochondrial fission were observed. A greatly increased incidence of caveolae was seen in the plasma membrane and in the mouth of t-tubules. The membranes of t-tubules showed vesiculation, especially near the dyads. Repeated administration of isoproterenol led to hypertrophy, characterized by the existence of myocytes with simultaneous signs of both mature and postnatally developing cardiomyocytes. Structural microheterogeneities at the level of individual cells may represent one of the factors leading to electrical imbalance in the myocardial tissue remodelled by isoproterenol.

Thoracic epidural analgesia and the cardiovascular system

Thoracic epidural anesthesia (TEA) with local anesthetics influences various aspects of the cardiac functions. It reduces the sympathetic tone, and it blocks the cardiac accelerator fibers. There is an overall decrease in the incidence of dysrhythmias, but not atrial fibrillation. TEA preserves left ventricular function and wall motion in patients undergoing cardiac surgery. Myocardial oxygen consumption is reduced with TEA while coronary perfusion pressure is maintained, thus protecting the heart from ischemic insults. The changes in clinical markers are not significant; however, Brain Natriuretic Peptide was reported to be reduced. Hypotension after TEA is partly the result of some cardiodepressant action and mostly due to arterial and venous vasodilatation. The inhibitory effect on the vasoconstrictor sympathetic outflow appears to be responsible for functional hypovolemia, but there are no changes in intravascular volume or in hemoglobin concentration. If the sympathetic block is limited to a few segments, there is a compensatory vasoconstriction in the unblocked areas. Otherwise, vasopressors remain the preferred treatment for hypotension over intravenous fluids when the block is extended to more than 6 to 8 dermatomes. TEA has been shown to increase the survival following hemorrhagic shock, but the block has to be initiated beforehand and should cover the thoracolumbar area.

Improved myocardial protection during coronary artery surgery with glucose-insulin-potassium: A randomized controlled trial

We sought to assess the role of glucose-insulin-potassium in providing myocardial protection in nondiabetic patients undergoing coronary artery surgery with cardiopulmonary bypass. A prospective, randomized, double-blind, placebo-controlled trial was conducted at a single-center university hospital performing adult cardiac surgery. Two hundred eighty nondiabetic adult patients undergoing first-time elective or urgent isolated multivessel coronary artery bypass grafting were prospectively randomized to receive glucose-insulin-potassium infusion or placebo (dextrose 5%) before, during, and for 6 hours after surgical intervention. Anesthetic, cardiopulmonary bypass, myocardial protection, and surgical techniques were standardized. The primary end point was postreperfusion cardiac index. Secondary end points were systemic vascular resistance index, the incidence of low cardiac output episodes, inotrope and vasoconstrictor use, and biochemical-electrocardiographic evidence of myocardial injury. The incidence of dysrhythmias and infections requiring treatment was recorded prospectively. The glucose-insulin-potassium group experienced higher cardiac indices (P < .001) throughout infusion and reduced vascular resistance (P < .001). The incidence of low cardiac output episodes was 15.9% (22/138) in the glucose-insulin-potassium group and 27.5% (39/142) in the placebo group (P = .021). Inotropes were required in 18.8% (26/138) of the glucose-insulin-potassium group and 40.8% (58/142) of the placebo group (P < .001). Fewer patients in the glucose-insulin-potassium group (12.3% [16/133]) versus those in the placebo group (23.4% [32/137]) had significant myocardial injury (P = .017). Noncardiac morbidity was not different. Glucose-insulin-potassium therapy improves early postoperative cardiovascular performance, reduces inotrope requirement, and might reduce myocardial injury. These potential benefits are not at the expense of increased noncardiac morbidity.

Ca 2+] i-dependent actions of taurine in spontaneously beating rabbit sino-atrial nodal cells

Modulation by taurine of the pacemaking activity and the underlying ionic currents in rabbit sino-atrial nodal cells was investigated at low and high cellular Ca 2+ concentrations ([Ca 2+] i) using a patch-clamp technique. At both pCa 8 and 6, taurine depressed the spontaneous activity, more strongly at pCa 6 than at pCa 8. Taurine, 20 mM, markedly inhibited the L-type Ca 2+ current: by 56.9±2.8% ( n=6, P<0.001) at pCa 8, and by 97.6±3.8% ( n=7, P<0.001) at pCa 6. Also at 20 mM, taurine decreased the delayed rectifier K + current by 26.8±2.6% ( n=6, P<0.01) at pCa 6, whereas taurine had less or no effect at pCa 8. The hyperpolarization-activated inward current also decreased at both pCa 8 and 6, by 18.3±1.3% ( n=8, P<0.05) and by 20.8±3.3% ( n=8, P<0.05) in 20 mM taurine, respectively. Taurine caused a more potent inhibitory effect at pCa 6. Taurine often elicited dysrhythmias, at 20 mM, in 3 of 17 cells at pCa 8 and in 12 of 16 cells at pCa 6. During washout, the incidence of dysrhythmias or arrest increased further. These results indicate that taurine exerts more potent inhibitory actions on ionic currents under Ca 2+ overload conditions in rabbit sino-atrial nodal cells. However, taurine would possibly elicit a cellular Ca 2+ overload, when taurine application was discontinued.

The hemodynamic effects of isotonic exercise using hand-held weights in patients with heart failure

Background: Controversy surrounds the use of resistance exercise in patients with heart failure because of concerns that increases in rate-pressure product and systemic vascular resistance might lead to increased afterload and decreased cardiac output. Methods Following pharmacologic left ventricular unloading therapy using a pulmonary artery catheter, 34 patients with advanced heart failure performed isotonic weightlifting exercise at 50%, 65%, and 80% of the calculated one repetition maximum. Measurements were made of hemodynamics, ST segment, rate-pressure product, serum norepinephrine, rating of perceived exertion, and dysrhythmias following each exercise set. Results Repeated analysis of variance showed significant increases in systolic blood pressure ( p = 0.0005), diastolic blood pressure ( p = 0.01), rate-pressure product ( p = 0.005); serum norepinephrine ( p = 0.004), and rating of perceived exertion ( p = 0.0005). However, systemic vascular resistance and cardiac output did not change significantly ( p > 0.05). Pulmonary capillary wedge pressures, the incidence of dysrhythmias, and ST segments did not significantly differ from baseline. No patients experienced angina or dyspnea during the study. Conclusions Isotonic exercise using hand-held weights was well tolerated hemodynamically and clinically, and no patients experienced adverse outcomes during exercise.

Effect of combined supplementation with vitamin E and alpha-lipoic acid on myocardial performance during in vivo ischaemia-reperfusion.

Reactive oxygen species (ROS) contribute significantly to myocardial ischaemia-reperfusion (I-R) injury. Recently the combination of the antioxidants vitamin E (VE) and alpha-lipoic acid (alpha-LA) has been reported to improve cardiac performance and reduce myocardial lipid peroxidation during in vitro I-R. The purpose of these experiments was to investigate the effects of VE and alpha-LA supplementation on cardiac performance, incidence of dysrhythmias and biochemical alterations during an in vivo myocardial I-R insult. Female Sprague-Dawley rats (4-months old) were assigned to one of the two dietary treatments: (1) control diet (CON) or (2) VE and alpha-LA supplementation (ANTIOXID). The CON diet was prepared to meet AIN-93M standards, which contains 75 IU VE kg-1 diet. The ANTIOXID diet contained 10 000 IU VE kg(-1) diet and 1.65 g alpha-LA kg(-1) diet. After the 14-week feeding period, significant differences (P<0.05) existed in mean myocardial VE levels between dietary groups. Animals in each experimental group were subjected to an in vivo I-R protocol which included 25 min of left anterior coronary artery occlusion followed by 10 min of reperfusion. No group differences (P>0.05) existed in cardiac performance (e.g. peak arterial pressure or ventricular work) or the incidence of ventricular dysrhythmias during the I-R protocol. Following I-R, two markers of lipid peroxidation were lower (P<0.05) in the ANTIOXID animals compared with CON. These data indicate that dietary supplementation of the antioxidants, VE and alpha-LA do not influence cardiac performance or the incidence of dysrhythmias but do decrease lipid peroxidation during in vivo I-R in young adult rats.

A Comparison of the Incidence of the Oculocardiac and Oculorespiratory Reflexes During Sevoflurane or Halothane Anesthesia for Strabismus Surgery in Children

We examined changes in the cardiorespiratory system of small children during surgical correction of strabismus with a laryngeal mask airway and spontaneous respiration with sevoflurane or halothane inhaled anesthesia. Fifty-one children, 1–7 yr old, having outpatient strabismus correction were randomized to sevoflurane (S) or halothane (H) in 66% nitrous oxide at 1.3 minimum alveolar concentration. Children breathed spontaneously through a laryngeal mask airway and were not pretreated with anticholinergics. The oculocardiac reflex (OCR), defined as a 20% decrease in heart rate (HR) from baseline, dysrhythmias, or sinoatrial arrest concomitant with ocular muscle traction occurred less frequently with sevoflurane than with halothane (S 38%, H79%, P = 0.009). The baseline HR was higher with sevoflurane (S 114 ± 13 bpm, H 101 ± 15 bpm, P = 0.002). The lowest HR occurred with halothane (S 95 ± 22 bpm, H 73 ± 19 bpm, P = 0.001). The incidence of dysrhythmias was higher in the halothane group (S 4%, H 42%, P = 0.004). Reductions in minute ventilation and PETCO2 accompanied OCRs. Airway irritability was present with halothane only (S 0, H 3). Eleven children, of whom the majority had received halothane, required measures to correct SpO2 < 95% or PETCO2 > 60 mm Hg during maintenance anesthesia (S 11%, H 32%). Sevoflurane may be a more suitable anesthetic than halothane for operations involving traction on the ocular muscles with spontaneous respiration in children because of reduced incidence of OCR, airway irritability, and ventilatory disturbances. Implications Some children experience a sudden slowing of the heart and impaired breathing when the surgeon pulls on the eye muscles during squint operations under anesthesia. Sevoflurane, a recently developed anesthetic vapor, may reduce this problem when compared with the established vapor halothane.

Gastric myoelectrical and antroduodenal motor activity in patients with achalasia.

Achalasia is a primary motor disorder of the oesophagus, in which the myenteric plexus is involved. However, abnormalities in other parts of the digestive tract have also been described in achalasia. Whether gastric myoelectrical and duodenal motor activity in these patients is also affected is unknown. Therefore, interdigestive and postprandial gastric myoelectrical and antroduodenal motor activity were studied in 11 patients with achalasia, using electrogastrography (EGG) and stationary antroduodenal manometry. Electrogastrographically, no differences were found in the gastric frequency, incidence of dysrhythmias and postprandial/fasting power ratio. In the interdigestive state a lower propagation velocity of phase III episodes was found in the achalasia patients, but other parameters were unaltered. Postprandially, no differences were found in the number of pressure waves, in the amplitude of pressure waves or in antroduodenal coordination. We conclude that gastric myoelectrical activity and antral motor activity in patients with achalasia is normal, suggesting an intact extrinsic and intrinsic neural innervation of the distal stomach. Although postprandial duodenal motility is normal, a lower propagation velocity of phase III suggests involvement of the small intestine in achalasia.

Oculocardiac Reflex During Retinal Surgery Using Peribulbar Block and Nitrous Narcotic Anesthesia

This study was designed to examine the effects of local and general anesthesia on the oculocardiac reflex (OCR) in adults during retinal detachment surgery, with an aim of determining the safest type of anesthesia and on which extraocular muscle traction causes a higher incidence of OCR. The study was performed on 30 American Society of Anesthesiologists-I patients (age range 40-60 years) who were undergoing retinal detachment surgery. Fifteen patients underwent surgery with general anesthesia and 15 were given a local peribulbar block. A fixed traction of 400 g was applied to all the extraocular muscles, and the heart rate, rhythm, and electrocardiogram of each patient was monitored. The overall incidence of OCR was higher with general anesthesia (63.3%) than with local anesthesia (14.4%). There was a significant decrease in heart rate for the rectus muscles (P < .0005) as well as the oblique muscles (P < .005) during traction with general anesthesia. All four rectus muscles were equally sensitive in eliciting the reflex. The incidence of dysrhythmias was 20% with general anesthesia and 6.67% with local anesthesia. This study showed that local anesthesia produces less bradycardia and ectopic arrhythmias and, therefore, may be safer and better than general anesthesia for surgeries in which traction of extraocular muscles is required.

Evaluation of Cardiac Rhythm Disturbances During Extravehicular Activity

This study represents the first systematic evaluation of dysrhythmias before, during, and after spaceflight including extravehicular activity (EVA). The data, based on 7 Shuttle crew members, revealed a nonsignificant decrease in ventricular and supraventricular ectopy during EVA, suggesting that the incidence of dysrhythmias is no greater during EVA than with any other phase of a mission or preflight.

Postoperative cardiac rhythms with superior septal approach and lateral approach to the mitral valve

The superior-septal approach provides an excellent view of the mitral valve and therefore has received considerable interest. However, the safety of this approach is controversial because it requires division of the sinus node artery in most cases. Postoperative cardiac rhythms were analyzed in 152 consecutive patients who underwent mitral valve procedures between January 1992 and February 1995 with a conventional right lateral left atriotomy (group 1, n = 69) or the superior-septal approach (group 2, n = 83). Follow-up ranged from 2 to 38 months, and the mean follow-up was 16.1 months in group 1 and 13.8 months in group 2. The mortality rate was similar in the two groups (1.4% in group 1 and 1.2% in group 2), and the causes of death were not related to the left atriotomy. At discharge, 96% of the patients in group 1 who were in sinus rhythm preoperatively and 78% of those in group 2 remained in sinus rhythm. At the last follow-up, 88% of these patients in group 1 and 83% in group 2 remained in sinus rhythm. Among the patients in atrial fibrillation or junctional rhythm before operation, 12% in group 1 and 11% in group 2 had regained sinus rhythm at the last follow-up. There were no significant differences in these values. Although the incidence of dysrhythmias was higher with the superior-septal approach in the early postoperative period, this approach provides an excellent operative view of the mitral valve and similar results in terms of late postoperative cardiac rhythms as the right lateral left atriotomy.

Gastric myoelectrical activity in patients with type I diabetes mellitus and autonomic neuropathy

In patients with diabetes mellitus and gastroparesis, dysrhythmias of gastric myoelectrical activity, especially tachygastrias, are thought to be involved in the pathogenesis of dyspeptic symptoms. Using surface electrogastrography we studied the prevalence of these abnormalities, and their relationships to dyspeptic symptoms and the extent of cardiac autonomic neuropathy in 30 euglycemic patients with type I diabetes mellitus and 12 controls. Neither in the fasting nor in the postprandial state were differences in mean frequency of gastric electrical control activity and its variability found between patients and controls. In the fasting state, the power content of the 3 cpm component in the power spectrum of the electrogastrogram was even higher in patients than in controls (P = 0.049). In the fasting state, second harmonics of the 3 cpm fundamental gastric signal were seen more often in patients than in controls (P = 0.03). In patients with symptoms during the study, no second harmonics were found after the meal. The postprandial/fasting power ratio was decreased in patients with symptoms during the study as compared to patients without symptoms and controls (P < 0.05). The incidence of dysrhythmias, such as tachygastrias and bradygastrias, was not higher in patients than in controls (17% and 8%, respectively). No correlation was found between electrogastrographic parameters and the severity of autonomic neuropathy or dyspeptic symptoms scored before the study. In conclusion, this study has shown that patients with type I diabetes mellitus and autonomic neuropathy studied under euglycemic conditions do not have grossly disturbed myoelectrical activity, except when symptomatic during the study.

Effects of Atracurium and Pancuronium on the Oculocardiac Reflex in Children

The authors compare the effect of two muscle relaxants, atracurium and pancuronium, on the bradycardia resulting from the oculocardiac reflex during eye surgery for strabismus in children. Two groups, each composed of 15 children, received either pancuronium or atracurium during strabismus operations. Heart rate and rhythm were observed at several points during the operations, and the changes that occurred in the two groups were compared. We found that the incidence and severity of the bradycardia, the incidence of dysrhythmias, and the need for atropine administration were significantly greater in the atracurium group than in the pancuronium group.

The patient's position influences the incidence of dysrhythmias during pulmonary artery catheterization.

To determine the influence of a patient's position on the incidence of dysrhythmias during pulmonary artery catheterization, 34 adult patients scheduled for elective coronary artery bypass graft surgery and pulmonary artery catheterization were studied. All introducers were inserted via the right internal jugular vein using the Seldinger technique with the patient in the Trendelenburg position. For each patient, the pulmonary artery catheter was advanced twice: once while the patient was in the Trendelenburg (T) position with a 5-10 degrees head-down tilt and another with a 5 degrees head-up and right lateral tilt (R) position. In 13 of the 68 pulmonary artery catheter passages, no dysrhythmias were noted. In 13 patients, a change in dysrhythmia classification was noted between the two positions. In 11 of the 13 patients, the dysrhythmia classification changed from malignant in the Trendelenburg position to benign or absent in the right lateral tilt position. Although the incidence of dysrhythmias was similar in both groups, the Trendelenburg position was associated with a significantly higher incidence of malignant dysrhythmias than the right tilt position (P less than 0.05). The authors conclude that the head-up and right lateral tilt position appears superior to the Trendelenburg position for passage of the pulmonary artery catheter in the awake patient scheduled for elective coronary bypass surgery.

Long-term follow-up of dysrhythmias following the Mustard procedure

Earlier reports have suggested that the incidence of dysrhythmias after the Mustard procedure can be reduced if the sinoatrial node (SAN) is protected during surgery. To determine if these initial differences continue after longer follow-up, we examined all ECGs available for three groups of patients operated upon from January, 1965, through December, 1977. Group A included 37 patients who survived the operation prior to January, 1972, when surgical modifications were initiated to protect the SAN; group B included 44 patients available for follow-up who were operated upon from 1972 through 1974; and group C consisted of the 39 patients available for follow-up operated upon from 1975 to 1977. Dysrhythmias were classified as passive (failure of initiation or propagation of the SAN impulse), active (atrial flutter or supraventricular tachycardia), or atrioventricular (AV) conduction defects. Results were expressed as the incidence per number of different rhythms during follow-up intervals. The incidence of sinus rhythm in groups B and C (80%) was much greater than in group A (27%) during the first 2 years. However, after 8 years, less than 50% of the rhythms were sinus. Both brady- and tachydysrhythmias were common. Seven patients (6%) required pacemaker insertion for symptomatic sick sinus syndrome. Therefore despite efforts to protect the sinus node, late occurring dysrhythmias remain a significant problem in the postoperative Mustard patient.

Perioperative Holter Monitoring and Computer Analysis of Dysrhythmias in Cardiac Surgery

In order to increase the accuracy and efficiency of studying perioperative dysrhythmias, 52 patients undergoing cardiac surgery were fitted preoperatively with a Holter monitor adapted for intraoperative recording, and the preoperative, intraoperative and early postoperative cardiac electrical activities were classified with a digital computer. Forty patients underwent coronary artery bypass grafting (CABG), eight had valve replacements, and four had combined procedures. The results showed the following: (1) high incidence of various dysrhythmias occurring during anesthesia induction and thoracotomy prior to aortic cross-clamp; (2) high incidence of continued atrial activity during cardioplegia; (3) lack of correlation between peak serum CPK-MB levels and dysrhythmias; and (4) a higher overall incidence of dysrhythmias in valve patients. Adapting the Holter monitor technique for cardiac surgery can solve the problem of observer vigilance inherent to such a study using a human "monitor watcher," and facilitate the accurate analysis of the vast amount of data obtained. This is important in quantitating the electrophysiologic effects of various perioperative interventions, such as the anesthetic agents, beta-blockers, calcium antagonists, and cardioplegic solutions.